A comparison of the reactions of cytochrome c oxidase, cytochrome c and azurin with Cr2+ ions.

Abstract The reduction of cytochrome c oxidase (EC 1.9.3.1) by Cr 2+ ions has been studied by stopped-flow spectrophotometry and is compared with the Cr 2+ reduction of cytochrome c and azurin. The effects of temperature, pH, and added anions (e.g., SCN − ) have been investigated. The behavior of the electron acceptor site of cytochrome c oxidase stands in contrast to that of the other redox proteins with regard to the effects of added anions and we suggest that this reflects the more buried nature of this site in the complex enzyme.